A typical refrigerator includes a freezer compartment that operates at a temperature below freezing and a fresh-food compartment that operates at a temperature between ambient and freezing. Typically, a damper or baffle is provided to control air flow between the freezer compartment and the fresh-food compartment. Conventional refrigerators include a refrigeration system having refrigeration components comprising a compressor, a condenser coil, a condenser fan, an evaporator, an evaporator fan and multiple single speed fans to direct the cool air throughout the freezer and fresh-food compartments. In addition, temperature sensors are provided inside the refrigerator to measure the temperature inside the freezer and fresh-food compartments. Conventional refrigerators also include an electronic control system to control non-refrigeration components, such as a user interface, lights, alarms, etc. but use conventional and less efficient timer-based methods to control the refrigeration components, such as the compressor, condenser, evaporator, etc. Thus, what is required is an electronic control system that controls all the components of the refrigerator including the refrigeration components to maximize efficiency.
In conventional refrigerators the refrigeration components operated at a single speed. Thus, when cooling was required, such as when a compartment door was opened, these systems were forced to operate a maximum level to cool the compartment down to its predetermined temperature. These single speed systems proved to be inefficient. In order to improve the efficiency of the refrigeration system variable speed systems having variable speed components were implemented where the speed of one or more of the refrigeration components is varied depending on the variation in temperature. These systems use several factors to vary the speed of the components, such as temperature of the freezer and fresh-food compartments, the ambient temperature, upper and lower temperature limits, etc. None of these systems, however, utilize all the factors to optimize the efficiency of the refrigerator system. Thus, what is required is a refrigerator system that utilizes multiple variables to vary the speed of the variable speed components to achieve optimum efficiency.
The present invention relates to a controller for achieving optimum efficiency by controlling various aspects of the refrigeration system. Similar refrigerators of this type are shown and described in the following U.S. patents, which are incorporated herein by reference: U.S. Pat. No. 5,201,888 to Beach, Jr. et al., U.S. Pat. Nos. 6,523,358, 6,694,755, and 6,837,060 to Collins, and U.S. Pat. No. 6,497,108 to Collins et al.